Process of making graphite.



Patentd Oct. I4, |902. E. G. ACHESUN. PROCESS 0F MAKIANEGRAPHHE.

(Application and pee. as, 1900.) y

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UNITED STATES PATENT OFFICE.

EDWARD GOODRICH ACHESON, OF NIAGARA FALLS, NEW YORK.

PROCESS OF MAKING GRAPHITE f SPF-CIFICATION forming part of Letters Patent No. 711,031, dated October 14, 1902 Application led December 22. 1900. Serial No. 4756. (No specimens.)

To @ZZ 7,071,079?, it may con/cern:

Be it known that I, EDWARD GooDEIoH ACHESON, of Niagara Falls, in the county of Niagara and State of NewYork,have invented a new and useful Process of Making Graphite, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of Ithis specification, in which- Figure l shows in vertical longitudinal section a furnace adapted for the practice of my invention. Fig. 2 is a vertical cross-section thereof on the line Il II of Fig. l.

Heretofore in accordance with the processes invented and patented by me graphite has been made in electric furnaces by subjecting to the intense heat of such furnaces carbon admixed either naturally or artificially with materials capable of forming carbids. I have now discovered a process whereby carbon, either devoid of such carbid-producing material or containing it in insufcient proportions or insufficiently distributed, may be converted into graphitic form. The invention is of great value, because it renders available materials which heretofore were not useful for this purpose, and it conduces greatly to the ease of manufacture and regularity and thorough graphit-ization of the product.

I have discovered that a very perfect transformation of amorphous carbon may be produced by causing metallic vapors to act upon the amorphous carbon at the high temperature which is obtainable in an electric furnace and that this can be brought about by subjecting metals or metallic compounds to heat in an electric furnace containing the amorphous carbon, thus volatilizing the metal or compound and causing the vapor thereof to permeate the mass of carbon which forms the charge of the furnace.

IVhile various formsof amorphous carbon may be used and the carbon may be drawn from various sources and various metals and compounds capable of determining the conversion of carbon into graphite may be employed forgenerating the vapor-such asiron, silicon, titanium, aluminium, boron, or compounds thereof-I will describe my process with reference to amorphous carbon obtained from the distillation of petroleum-oil, known in commerce as petroleum-coke,7 and with iron as the metallic agent. In an electric furnace which-may be constructed, as shown in Fig. 1, with electrodes 2 2 extending into it at the ends, I place petroleum-coke, broken t0 such state that its particles vary in size from a powder to linups measuring, say,'three inches or four inches in diameter and preferably in such pr'oportion that the lumps are fully and completely embedded in the powder. Through this mixture I scatter or roughly mix oxid of iron in the proportion of, say, five pounds of iron to one hundred pounds of coke. I also place in the furnace extending through the charge a conductor composed, preferably, of carbon rods or plates 3 3, which are' in contact with each otherand are connected with electrodes at the ends of the furnace. The entire charge of-coke (indicated in the'drawings by the reference-numeral 4) is preferably covered with an air-excluding layer of nonheatconducting material, which may be sand and powdered carbon in proper proportion to form carbid of silicon. The furnace being thus charged au electric current is caused to pass through the carbon rods embedded in the charge mixture.

Vith a furnace of, say, thirty feetin length, fourteen inches in Width, and eighteen inches deep a current of about two hundred volts and three hundred amperes is suitable. This current will `quickly increase in volume as the result of the lessened resistance ofthe carbon rods and of the surrounding coke as the temperature increases.

After the operation is complete, which is indicated by a great reduction of the resistance, and when sufficient time has elapsed for the cooling of the contents of the furnace the covering of sand and carbon, which has been partially converted into carbid of silicon, is removed and the coke which has been converted into soft graphitic carbon is taken from the furnace.

During the operation of the furnace the oxid of iron that has been scattered throughout the carbonaceous material is first reduced, the iron being brought to the metallic state, and the reduced iron is either held in the cavities and interstices of the pieces and lumps of coke or settles in a mass to the floor of the furnace, whence as the operation continues and the temperature rises it is volatilized and IOO more or less fills the entire furnace, thus coming into intimate contact with the carbon contained therein, and, as I have discovered, itproduced at the high temperature employed the conversion of the amorphous carbon into graphite.

The function of the rods above described is to serve as a preliminary conductor for the current, and as such conductor is not essential to my invention it may be constituted in Various Ways and forms or may be omitted Where the carbon to be graphitized is suft'lciently conduct-ing. The form and construction of the furnace may be modified Without Y departingfrom the principles of myinvention. It is also possible to vary the relative amount of the metallic element employed.

From the foregoing description those skilled in the art Will be enabled to employ my in- Vention in the graphitization of various kinds of amorphous carbon and to use in the process various kinds of metals or metallic compounds as the source of the vapor by which the charge of the furnace is permeated.

I claim as my inventionl. The method herein described of making graphite, which consists in introducing into an electrical furnace a mass of carbon to be graphitized, in the form of lumps, and also introducing thereinto a volatilizable material capable of forming a carbid, and heating the same to a high temperature, vapcrizing the volatilizable material, thereby causing the vapor to permeate the charge of lumps and to graphitize the same; substantially as described.

graphite, which consists in introducing into an electrical furnace a mass of carbon in the form of discrete lumps embedded in powdered carbon, and also introducing thereinto a volatilizable material capable of forminga carbid, and heating the mass to a high temperature sufcient to vaporize the said element or compoundy and to graphitize the carbon; substantially as described.

4. The method herein described of making graphite, which consists in introducing into 'an electrical furnace a mass of petroleum@ coke to be graphitized, and also introducing thereinto a volatilizable material capable of forming a carbid, and heating the same to a high temperature sufcient to vaporize the said volatilizable material and to graphitize the carbid; substantially as described.

In testimony whereof I have hereunto set my hand.

EDWARD GOODRICI. ACIIESON.

Witnesses:

H. M. CORWIN, G. B. BLEMING. 

